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Just back from my two presentations and I've uploaded the final versions (which replace the ones distributed on the conference CD).

When I give presentations I have to find something to display the time (since I never wear a watch), somewhere to put some speaker notes down (since I sometimes forget a useful point), and then I keep knocking it all over everytime I go to the laptop to hit space to get the next slide. I'd quite like to use the laptop display to display my speaker notes and a clock, but OpenOffice doesn't support doing that yet.

I recently changed to using a smartphone to save carrying around and having to recharge lots of gadgets. I bought a Mio A701 which is a nice phone, PDA, and has GPS in one package. Since the Mio also has bluetooth I thought that for my presentations at the Red Hat Summit next week it would be nice to use the PDA to control the presentation, watch my time, and give me any speaker notes.

The smartphone runs Windows Mobile 5, unfortunately and I wanted to set something up quickly and without much effort. I don't mind writing apps for it, but I'd rather avoid it. So my first thought was to use vnc, but the vnc client on the pocketpc wasn't great and kept crashing, and I'd have to create some app to interface with OpenOffice anyway. Once OpenOffice supports multiple displays it may be more useful to revisit doing this via vnc.

My laptop runs Fedora Core 5 with a MSI bluetooth USB dongle plugged in.

Step 1: Get the phone talking to the laptop

This should have been the easiest step, but took an hour to get working right as I originally struggled getting the phone to connect to a 'serial port' service. The commands below were sufficient to advertise a 'dial up network' service and have pppd handle the connection. I didn't bother setting up any IP forwarding as I don't need the phone to be able to use the laptop as a way to get generic network access.

   /sbin/service bluetooth start
   sdptool add --channel=2 DUN
   dund -u --listen --channel=2 --msdun noauth \
      crtscts 115200 ms-dns lock
Then on the Windows Mobile I added a new connection, selected "bluetooth" modem, created a new partnership with the laptop DUN service, any phone number, any username and password (to stop it prompting later), advanced to remove the "wait for dial tone" option. If you're doing this from scratch you'll need to play with settings in /etc/bluetooth/hcid.conf to make sure you set up a PIN for pairing and so on.

Once this is done using the browser on the phone with a URL of causes it to connect, pppd starts, and the phone happily can connect to the web server on the laptop. If you want DNS working you'll need to mess with the dns IP above or make sure your laptop DNS server is set up to accept connections on that interface. So far so good.

Step 2: Control the presentation

The next step was to be able to control the presentation. I couldn't see any nice way to remotely control, so a colleague suggested finding something that used the xtest extension just to inject keystrokes. the X11::GUITest perl module on CPAN does the job perfectly. So I hacked up a quick perl script you run as your local user that acts as a web server and on certain requests will inject a space character into whatever has focus.

pic of the setup

Step 3: Speaker Notes

Next step is to get the mini perl webserver to display my speaker notes as well as the link to the next slide, although, to be honest, I could probably have committed the notes to memory in the time it took to set this all up.

Download the trivial little perl script

The biggest problem with my home-grown Home Automation system was that I'm not a graphic designer. My displays all looked a little clunky, like they'd come out of the 1980s. Guests only ever see the user interface displayed on the tablets around the house, so I took some time over the Easter holiday to make the user interface look a bit nicer.

The user interface is written in Perl/Tk and was designed to be snappy even on the original Point 510 (100Mhz) tablets. I'd already replaced these tablets around the house with Point 1600 tablets (most picked up on ebay for about 50-100 pounds each) with the main advantage that the Point 1600 can run at 800x600 in full-colour rather than the 256 colours of the 510 in the same resolution.

I first looked around the web to see if there were any existing Perl/Tk projects that had exciting graphic design I could base on, but I didn't find anything very useful. In the end I decided to make the UI look like a web site design proposed by a colleague at Red Hat for some internal site that didn't get used.

Screenshots from the new design


The Heating interface lets you look at graphs of past readings for any sensor or change the target temperature of the house.


Actually we only have a couple of X10 lights in the house, and we really only ever control the living room lights.


This is just screen-scraped from the BBC website and updated every hour.


We use this screen to look at the security cameras as well as some other Glasgow web cameras. The interface allows multipart-jpeg streaming (compatible with ZoneMinder).


This actually displays a number of events such as the status of the house alarm, capturing when the doorbell is pressed, as well as popping up details of who calls us.

Screenshots of the original design

Old heating interface for comparison. See my original software page to see how the other screens looked.


I was previously using the Tk/TabBar module from Jarl to provide the nice tab bars, and a bit of hacking gave the simplified tabbar (with the advantage that the bar will still nicely wrap over two rows if needed)

The rest of it was just messing around with frames and alignment and creating the curved edges. I used the gimp to get a curve I was happy with, then coverted it from a GIF to xpm with reduced colours. The xpm was then coded into the application and simplified so that the program can generate the right curves for any font size.

The Perl/Tk I used to create the headings is available here and running that program displays the following:

Remember all those reports which compared the number of security vulnerabilities in Microsoft products against Red Hat? Well researchers have just uncovered proof and an admission that Microsoft silently fix security issues; in one case an advisories states it fixes a single vulnerablity but it actually fixes seven.

Whilst you could perhaps argue that users don't really care if an advisory fixes one critical issue or ten (the fact it contains "at least one" is enough to force them to upgrade), all this time the Microsoft PR engine has been churning out disingenuous articles and doing demonstrations based on vulnerability count comparisons.

My home automation tablets use Perl/Tk as their user interface which makes coding and prototyping really quick and easy and works on both Linux and Windows platforms. I use ZoneMinder for looking after the security cameras around the house and had set up the tablets to be able to display a static image from any camera on demand. But what I really wanted to do was to let the tablets display a streaming image from the cameras.

ZoneMinder is able to stream to browsers by making use of the Netscape server push functionality. In response to a HTTP request, ZoneMinder will send out a multipart replace header, then the current captured frame as a jpeg image, followed by a boundary string, followed by the next frame, and so on until you close the connection. It's perhaps not as efficient as streaming via mpeg or some other streaming format, but it's simple and lets you stream images to browsers without requiring plugins.

So I wrote the quick Perl/Tk program below to test streaming from ZoneMinder. It does make some horrible assumptions about the format of the response, so if you want to use this with anything other than ZoneMinder you'll need to edit it a bit. It also assumes that your network is quite good between the client and ZoneMinder; the GUI will become unresponsive if the network read blocks.

My first attempt ran out of memory after an hour -- I traced the memory leak to Tk::Photo and it seems that you have to use the undocumented 'delete' method on a Tk::Photo object otherwise you get a large memory leak. The final version below seems to work okay though.

# Test program to decode the multipart-replace stream that
# ZoneMinder sends.  It's a hack for this stream only though
# and could be easily improved.  For example we ignore the
# Content-Length.
# Mark J Cox,, February 2006

use Tk;
use Tk::X11Font;
use Tk::JPEG;
use LWP::UserAgent;
use MIME::Base64;
use IO::Socket;

my $host = "";
my $url = "/cgi-bin/zms?mode=jpeg&monitor=1&scale=50&maxfps=2";

my $stop = 0;
my $mw = MainWindow->new(title=>"test"); 
my $photo = $mw->Label()->pack();
$mw->Button(-text=>"Start",-command => sub { getdata(); })->pack();
$mw->Button(-text=>"Stop",-command => sub { $stop=1; })->pack();

sub getdata {
    return unless ($stop == 0);
    my $sock = IO::Socket::INET->new(PeerAddr=>$host,Proto=>'tcp',PeerPort=>80,)
    return unless defined $sock;
    print $sock "GET $url HTTP/1.0\r\nHost: $host\r\n\r\n";
    my $status = <$sock>;
    die unless ($status =~ m|HTTP/\S+\s+200|);

    my ($grab,$jpeg,$data,$image,$thisbuf,$lastimage);
    while (my $nread = sysread($sock, $thisbuf, 4096)) {
        $grab .= $thisbuf;
        if ( $grab =~ s/(.*?)\n--ZoneMinderFrame\r\n//s ) {

            $jpeg .= $1;
            $jpeg =~ s/--ZoneMinderFrame\r\n//; # Heh, what a
            $jpeg =~ s/Content-Length: \d+\r\n//; # Nasty little
            $jpeg =~ s/Content-Type: \S+\r\n\r\n//; # Hack

            $data = encode_base64($jpeg);
            undef $jpeg;
            eval {
                $image = $mw->Photo(-format=>"jpeg",-data=>$data);
            undef $data;
            eval {
            $lastimage->delete if ($lastimage); #essential as Photo leaks!
            $lastimage = $image;
        $jpeg .= $1 if ($grab =~ s/(.*)(?=\n)//s);
        last if $stop;
    $stop = 0;
Russell Handorf used threads to support more than one camera at a time (although I would probably do this in a loop or with select instead of threads)

I use a Dallas 1-wire network for temperature sensing and control around the house. Ideally you run a single cable from the PC interface and attach sensors along the wire, but I didn't think of that before the house was wired. So instead I use a star network using the existing cat5 networking to each room, with a one-wire hub from AAG handling switching between the different spokes of the hub.

At the Home Automation server is a USB to 1-wire interface unit. This interface connects directly to the one-wire hub. 6 outputs from the hub go to various places around the house.

Output C6 has a ds18s20 temperature sensor plugged straight into it, this provides the temperature of the home automation cupboard.

Output C5 goes to the lounge, which has a single ds18s20 temperature sensor plugged straight into it, this provides the temperature of the lounge which is used as the master control for the heating system.

Output C2 goes to the master bedroom, again with a single ds18s20 temperature sensor.

Output C1 goes to the garage, where a temperature sensor is connected and poked out of the vent to get the outdoor temperature, and on the same wire is a 1-wire switch used to control the heating system.

The final output C4 goes to a hacked wireless doorbell. A one-wire switch detects when the doorbell is activated. The one-wire hub provides a 5v supply and so we use this to power the doorbell to save on batteries.

The home automation sensor polls each device in turn to get a reading. For short events (like a doorbell push) it monitors a latched register which shows if the state of the input has changed since the last time the device was polled. I'll write more about the software side of this and give my source code in a later article.

More photos of 1-wire:

see all at

In March 2005 we started recording how we first found out about every security issue that we later fixed as part of our bugzilla metadata. The raw data is available. I thought it would be interesting to summarise the findings. Note that we only list the first place we found out about an issue, and for already-public issues this may be arbitrary depending whoever in the security team creates the ticket first.

So from March 2005-March 2006 we had 336 vulnerabilities with source metadata that were fixed in some Red Hat product:

111  (33%)  vendor-sec
 76  (23%)  relationship with upstream project (Apache, Mozilla etc)
 46  (14%)  public security/kernel mailing list
 38  (11%)  public daily list of new CVE candidates from Mitre
 24   (7%)  found by Red Hat internally
 18   (5%)  an individual (issuetracker, bugzilla, secalert mailing)
 15   (4%)  from another Linux vendors bugzilla (debian, gentoo etc)
  7   (2%)  from a security research firm
  1   (1%)  from a co-ordination centre like CERT/CC or NISCC
(Note that researchers may seem lower than expected, this is because in many cases the researcher will tell vendor-sec rather than each entity individually, or in some cases researchers like iDefense sometimes do not give us notice about issue prior to them making them public on some security mailing list)

Last year I wrote about how both Red Hat and Microsoft shipped the third party Flash browser plugin with their OS and whilst we made it easy for users who were vulnerable to get new versions, Microsoft made it hard. With another critical security issue in Flash last week, George Ou has noticed the same thing.

Just finished the security audit for FC5 - For 20030101-20060320 there are a potential 1361 CVE named vulnerabilities that could have affected FC5 packages. 90% of those are fixed because FC5 includes an upstream version that includes a fix, 1% are still outstanding, and 9% are fixed with a backported patch. Many of the outstanding and backported entries are for issues still not dealt with upstream. For comparison FC4 had 88% by version, 1% outstanding, 11% backported.

What defines transparency? The ability to expose the worst with the best, to be accountable. My risk report was published today in Red Hat Magazine and reveals the state of security since the release of Red Hat Enterprise Linux 4 including metrics, key vulnerabilities, and the most common ways users were affected by security issues.

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Hi! I'm Mark Cox. This blog gives my thoughts and opinions on my security work, open source, fedora, home automation, and other topics.